Generally, there are three production processes for stainless steel composite plates, namely direct rolling method, explosive composite method and explosive welding and rolling comprehensive method. These methods correspond to different stainless steel thicknesses, ratios, varieties, specifications and processing requirements, and can basically meet various common usage needs.

Let’s talk about the rolling cladding method first. This is a method of producing stainless steel clad plates using pressure processing technology. It is divided into two types: cold-rolled cladding and hot-rolled cladding. Its principle is to send the two metals to be composited into the rolling mill for rolling according to certain ratios and requirements. Under the strong pressure of the rolling mill, or combined with heat, the two composite stainless steels are The metal plate produces plastic deformation on the entire cross-section, so that after the composite surface is deformed and cleaned, a planar metallurgical bond is formed.

The requirements for rolling cladding are rolling equipment with strong pressure and professional technology for producing clad steel plates. Composite panels manufactured using this method have the following advantages: they can expand the size of the composite panel, that is, length and width; the production cost is lower, and stainless steel products have good competitiveness in the market; they can be continuously produced from raw materials to finished products, which is suitable for Mass production; it is easy to establish a production line with a relatively high degree of automation; the clad material is not easily contaminated by the base material, has good bonding performance, and the quality of the composite board is more stable.

Let’s talk about the explosive composite method. This is a new composite plate processing technology that uses explosives as energy to weld two or more metal plates with different properties, especially those that are incompatible, into one. Compared with the rolling composite method, the advantage of this method is that the loading speed is faster; the high-voltage pulse load applied to the stainless steel workpiece, the loading stress is much higher than the yield strength of the metal material; third, the bonding zone exhibits wavy metallurgical bonding characteristics . It is more difficult to realize automated production, and the labor intensity of workers is relatively high, and its production cost is also relatively high.

The principle of this method is to install the two metal plates to be composited in a certain way, place special explosives on the composite material, and place the detonator in a specific position. When the explosive is triggered, the high-voltage pulse load generated by the explosion acts on the composite board, and the composite board is accelerated to a speed of several hundred meters per second within a few microseconds. Starting from the detonation position, the clad plate successively collides obliquely with the base plate. The pressure generated by the collision of the two plates greatly exceeds the dynamic yield limit of the metal. In the area adjacent to the collision point, high-speed and strong plastic deformation occurs, accompanied by a certain degree of plastic deformation. adiabatic effect. The surfaces of the two metal plates to be bonded behave like fluids in an instant, forming two metal jets with opposite motion directions. The free jet located in front of the collision point ejects at high speed into the space of the unbonded area, washing away the two metal plates. The oxide film, pollutants, etc. on the surface to be combined reveal a clean active surface, which provides the necessary conditions for welding; the convex angle jet after the collision point is "solidified" between the two metal plates to form a wavy Metallurgical bonding characteristics.

The third method is the explosive welding and rolling comprehensive method, which uses explosive composite welding technology to weld two or more metal plates to be combined according to the corresponding thickness ratio to form a composite slab, and then weld it according to different thicknesses. According to the conditions and requirements, hot rolling or cold rolling can be made into composite steel plates with required thickness specifications. This method is a new joint technology developed by combining the respective advantages of explosive composite technology and rolling technology. Its advantages are as follows: explosive composite billet making, which ensures the welding quality of the joint area of two or three layers of metal plates; reduces the difficulty of rolling composite billet making; and the process has high production efficiency and good yield; stainless steel The dimensional accuracy of the composite plate is high and the surface quality is better. Finally, this method can produce large-scale production of various types of composite stainless steel plates without welds.

Introduction to the production process of stainless steel composite panels

The generally widely used processes for producing stainless steel composite plate materials are solid-liquid phase combining method and solid-phase combining method. Among them, the most common solid phase bonding method is essentially explosion welding and explosion welding billet plus rolling method. It also includes stacked plate hot rolling method, diffusion crimping method, cladding welding method, cladding hot rolling method, etc. Craftsmanship.

When the explosion welding process is used to produce stainless steel composite panels, explosives are used as the energy medium to weld the metal materials. The shock wave formed by the explosion is used to push the composite panel to move to the substrate at high speed. While the gas in the gap is discharged, the gas in the gap is impacted and formed on the contact interface. The plastic deformation, melting and inter-atomic diffusion of a thin layer of metal ultimately leads to the welding of different metal plates.

"Explosion welding billet plus rolling" is a process method that performs rolling processing on the basis of explosion welding. It mainly involves the research and development of cold-rolled double-sided composite coils. Through different production methods, the composite of stainless steel composite panels can be divided into two types: single-sided composite and double-sided composite; the shapes are divided into plates, tubes, wires, rods, wires, and conductive composite materials.

Taiyuan Iron and Steel mainly uses explosive welding to directly produce stainless steel medium plates. The bonding interface of explosion welding is corrugated, which is also different from the interface of direct rolling composite. The presence or absence of such corrugated interface is regarded as an important indicator of whether the welding is good. From the metallographic point of view of the sample, there are usually three types of explosive composite interface bonding forms: one is the direct bonding between metals; the second is the wave-like bonding at the interface; the third is the formation of a uniform and continuous molten layer between metals . Among these three forms, only the wavy bonding and atomic diffusion between the interfaces can allow the stainless steel composite plate to have a relatively high interface strength and at the same time be able to be processed within a wide range of process parameters. It is a very The ideal combination method.

The most critical step in the production process of stainless steel composite plates is the heat treatment process. After explosion welding, the strength and hardness of the composite steel plates are relatively high, and the plasticity is reduced, which is not conducive to the processing and use of subsequent processes. The process of heat treatment is essentially to remove the internal stress after explosive recombination and increase the plasticity. However, because there is a big difference between the solution treatment system of ordinary stainless steel materials and the heat treatment system of carbon steel, the selection of heat treatment temperature, holding time and cooling system is very important.

Another key indicator that affects welding performance is material selection, which is also an important step in equipment assembly and production. Compared with pure stainless steel plates and carbon steel, the welding process of stainless steel composite plates is significantly different. Taking the stainless steel composite medium-thick plate produced by explosive welding as an example, there are three main types of welds: base welds, cladding welds, and transition layer welds.

Stainless steel composite steel plates have also begun to be widely used, including petrochemical, machinery, food, decoration and other industries. In addition, there will be more and more applications in daily life, such as water tanks, advertising light boxes, flagpoles, guardrails, doors and windows, etc.